System shutdown due to Automove property of file system

In z/OS, many patches need to be restarted before the system can take effect. In the Sysplex environment, it is often used in the form of rolling IPL, that is, the mass shutdown system, rather than all systems shut down together. In this process, the abnormal shutdown of the USS system often causes the shutdown process of the entire system to not proceed normally. One reason for the USS System not to shut down properly is the file system owner Setup issue. This article will combine with the actual example, explained because the file system Automove attribute setting, causes the USS not to shut down normally the phenomenon.

Terminology Explanation:

Before explaining the specific examples, the paper first explains several professional terms involved in the article.

1. Sharing file system environment (shared filesystem environment)

2. Users in a shared file system environment can access all systems in a shared environment by logging on to a system in the Sysplex environment. For example, there are two systems SYS1 and SYS2 in Sysplex, and after the user logs on to SYS1, they can access both the directories and files under SYS1 and the files in the SYS2.

3. File System Owner:

It is still assumed that there are two systems in the Sysplex environment, SYS1 and SYS2. How can users who log on to SYS1 access the file system in SYS2? This needs to send a request from SYS1 to SYS2, request SYS2 to complete the corresponding operation for SYS1, this process is called function-shipping. Here, SYS2 acts as the actual operating file system, so SYS2 is called owner of the filesystem, and SYS1 is called the client of the file system.

The owner, referred to here, is the USS owner, and for the ZFS file system and ZFS owner, the two owner functions are completely different. Please refer to the distributed File Service for readers who are interested in two kinds of owner without discussion

ZSeries file System Administration The ZFS ownership versus z/OS UNIX ownership of file systems.

4. Automove

Automove is a parameter that specifies where the file system will go when the system shuts down.

The so-called "go" has a number of situations: Owner move into another system (Yes), uninstall (unmount), do not move (no), owner moved to the specified system (Include systems list), owner do not move to the specified system (exclude Systems list). The command format is as follows:

–a yes|include,sysname1,..., sysnamen|exclude,sysname1,..., sysnamen|no|unmount

Specific explanation parameters:

Yes: If the owner of the specified file system becomes a different system when the system shuts down, it means that although the current owner of the filesystem is turned off, because its owner becomes a different system, the filesystem is "alive" in this Sysplex and still can be accessed by the program.

No: The owner is turned off, the file system owner is not moved, and the file system becomes inaccessible.

Unmount: If the specified file system is unloaded when owner is shut down, that means the system is down and the file system is unloaded at the same time, becoming inaccessible.

Include: The owner of the current filesystem is moved sequentially, sequentially, to several systems specified by include. For example, the current owner of the file system is SYS0, if the include SYS1,SYS2,SYS3 is specified then when SYS0 is closed, if SYS1 is active, owner becomes SYS1 and if SYS1 is closed, Then owner will become SYS2, and so on.

Exclude: Meaning that after owner is turned off, owner of the filesystem cannot be moved to the following system specified.

For example, use the following command to mount a ZFS file system OMVSSPN.JX1.LDAPDATA.ZFS to/jx1/ldapdata, requiring that the owner of the filesystem system be JX1 and uninstalled when the system shuts down. The command looks like this:

Mount-t zfs–d jx1-a unmount-f omvsspn. JX1. Ldapdata. Zfs/jx1/ldapdata

For a detailed explanation of the command format, see UNIX System Services command Reference

Example Explanation:

When a USS system on an image is closed, it usually executes such a command:

F Bpxoinit,shutdown=fileowne. The purpose of this command is to uninstall all file systems on the system and to prevent the system from becoming owner of another file system. In this process, the system gradually unloads the file system from the smallest child node of the filesystem. For example, for path/jx1/ldapdata, each level path has a file system mount above it. As shown in the following command:

128:/u/xiarz $ df-kvp/jx1

FileSystem 1024-blocks Used Available Capacity mounted on

Omvsspn. JX1. SYSTEM. ZFS 259920 116801 143119 45%/jx1

ZFS, Read/write, device:51230, acls=y

Rwshare

File System owner:jx1 automove=n client=n

Filetag:t=off codeset=0

Aggregate name:omvsspn. JX1. SYSTEM. Zfs

129:/u/xiarz $

129:/u/xiarz $

129:/u/xiarz $

129:/u/xiarz $ df-kvp/jx1/ldapdata

FileSystem 1024-blocks Used Available Capacity mounted on

Omvsspn. JX1. Ldapdata. ZFS 100080 4449 95631 5%/jx1/ldapdata

ZFS, Read/write, device:51237, acls=y

File System owner:jx1 automove=u client=n

Filetag:t=off codeset=0

Aggregate name:omvsspn. JX1. Ldapdata. Zfs